Pages

Monday, March 05, 2007

Editor’s note: this is an expanded version of the article that appears in the April 11, 2007 issue of Radio World, which can be found at http://www.rwonline.com/

Correction: the printed article says that you cannot program a preset to an HD2, HD3, etc multicast channel. I realized, too late for press time, that this is not true...you can program a preset to a multicast channel, although there is the expected buffering delay of several seconds when you tune to it.

One big missing component of the HD Radio tuner rollout has been the HD equivalent of ubiquitous alarm clock radios.For a while we’ve had only the Boston Acoustics Receptor HD; now we also have the Directed Electronics DHHD1000 tabletop receiver…and it’s pretty good, overall.

This article will put the DHHD1000 head to head against the Receptor HD, and I’ll also toss in some comparisons to my Sangean HDT-1 component HD tuner.

Unpacking the DHHD1000…

Whoever put this together has been listening to engineers’ early laments about a lack of good antennas; a well-built AM loop and FM dipole antenna were included, as well as two outboard speakers that’re nearly as big as the radio themselves.Rounding things out were a headphone jack and aux input on the back (along with a mysterious “Service Only” s-video jack), a “wall wart” power supply and an instruction manual.

Being a typical engineer, I put aside the manual for the moment; I wanted to see how intuitive everything was.For the basic setup, it was all quite easy to get the unit powered on and listening to HD Radio.There is a menu button, but for most day-to-day functions you’ll be using the other six buttons: power, band, tune up, tune down, preset, memo(ry) and the volume knob.Push in the volume knob to switch to the “Aux” input.Plugging in headphones mutes the speakers.The radio automatically switches to the HD signal if it detects one strong enough to lock onto.Lacking HD, it’ll show RBDS PAD if one is present.

The good stuffThis quickly led to the first treat of this radio, you can set the display to “program guide”.This means that if a multicast channel is detected, it’ll show the PAD from that multicast stream, and the main channel’s PAD at the same time.So you can listen to one channel, and if you spy something you want to hear on the other channel, it’s a simple matter to tune one spot over.

The sensitivity of the radio also quickly became apparent when I moved to the NCE band, a place where Boston has over a dozen college stations all crammed next to each other.I live barely 2 miles from 1000 watt WZBC on 90.3, so I tried tuning in WICN – an 8000 watt directional on 90.5 over 30 miles away on roughly the same azimuth.Surprisingly, WICN was there!Admittedly there was a fair amount of static, more than I’d consider “listenable” for any length of time, but there was no crosstalk from WZBC.

Next test is on the AM band.We only have three stations in Boston proper running HD on AM: WBZ 1030, WMKI 1260 and WXKS 1430.All three blended to HD within a few seconds of tuning and the improvement in audio quality is dramatic: much more high end, and all stereo.Some minor audible artifacts, but overall I’d say it’s much better than regular AM.An added treat showed up when I tuned to WJIB – this radio continues the trend of HD tuners decoding C-QUAM AM Stereo!I wouldn’t quite call it as good as HD, but it’s not bad.

Finally, after warning my wife, I cranked up the volume on a few stations to see what the supplied amplifier could do.I wouldn’t say it “goes to eleven”, but it’s more than loud enough for most any domestic situation.

T

he next morning I got to test the unit’s two alarm clocks.Either can be set to any time, and set to buzz or play the radio.An added bonus: you can even set the volume of the buzzer or radio.Programming it all is a little tricky, but the buzzer sounds disturbingly like a modern fire alarm/klaxon, which really gets ya out of bed, I can assure you!There’s also a snooze/sleep button.

Removing eight screws from the rear reveals a sparse interior.Most of the electronics are packed along the front, bottom and one side; there’s a lot of empty space for something so remarkably small to begin with, although the unit still draws 1.5A at 12VDC…quite a bit.

The not-so-good stuffSo far, I’ve been pretty impressed with this little unit.But now we come to the downsides.First is audio quality; the supplied speakers are fairly small, and despite attempts at bass ports in the back, there’s just not much “oomph” on the low end at all.There’s also no EQ or even bass/treble “tone” controls.I tried hooking up my trusty set of Technics LX-50 home stereo speakers, and the lack of bass was noticeable even on those.Ditto for headphones.Using the aux port with my iPod set to “bass booster” there was better sound, but I had to turn up the gain very high just to get normal listening volume…high enough that some minor distortion was evident.I think there’s just no way to get a silk purse out of this sow’s ear, but hey – it’s a table radio.

While the radio can hold 30 presets, programming them is a somewhat tedious process, although the radio does hold on to your presets (and the clock) during a power outage, though.

I also noticed that receiver sensitivity for FM drops dramatically depending on how the antenna is oriented.Many non-savvy listeners just ball up the antenna wire, and doing that on this radio makes it pretty “deaf”…and there’s no mention of how to properly orient a dipole antenna.

This brings me to a somewhat-damning problem: the documentation.Or should I say, lack of it.There’s a small and sparse booklet that’s filled with confusing yet repetitive info…most of it in badly-translated “Engrish”. Check it out for yourself in this PDF I scanned in. Fortunately, most of the radio is pretty intuitive, but the lack of good documentation could be a deal-killer for non-technical folks.

A call to Directed Electronics took several transfers to get to their technical support department, who reports that there are no "hidden features" sometimes found on early HD Radios...like the ability to force one speaker to analog and the other to digital so as to time-sync them by ear. Or force the radio into analog-only or digital-only. Admittedly, I wasn't really expecting any such features on this unit, however.

My eyes! My eyes!

Another major gripe I have is the display’s ultra-bright blue backlight.It’s comparable to that searingly bright neon from Kramer’s apartment in Seinfeld’s “Chicken Roaster” episode.Even with the ten-stage dimmer at its lowest setting it’s still pretty bright for a dark bedroom.Clearly this radio is designed for bedroom alarm clock use, so the display issue seems a major oversight.

Stacking up against the Boston Acoustics Receptor HDWith the DHHD’s dipole feeding a co-ax antenna splitter to both radios, the real test of the DHHD1000 vs. the Receptor HD was ready; FM signals across the board took a hit with that splitter, and the inherently weaker HD carriers (by definition they are -20dB / 100 times weaker than analog) now became a challenge to receive.

A good test case was WUMB 91.9FM, a 660 watt ERP analog / 6.6 watt ERP digital station approximately 10 miles away.I was just barely inside their protected service contour, so any HD reception would be “on the edge”.

Not surprisingly, HD reception was next to impossible.But with a careful arrangement of the dipole, I was able to find “the edge” of getting an HD signal.I found that both radios would lose or acquire the HD signal from WUMB at about the same point.A similar test with another mid-powered Class A, WKAF 97.7FM, demonstrated similar results.If anything the Receptor HD seemed more able to stay locked on to a medium HD signal, although the DHHD1000 was better at acquiring a weaker HD signal…but the difference was pretty small.With the same antenna, I’d judge both radios to be about the same in FM sensitivity.

However, the Receptor HD comes with a much-maligned “rat tail” wire antenna that is horrible in general…never mind compared to the DHHD1000’s quite-decent dipole.So “out of the box” the Directed Electronics wins the FM sensitivity challenge.

AM is harder to measure with separate loop antennas, but careful placement in the same location yielded fairly similar sensitivity on both radios for both WBZ and WMKI. WXKS, on the other hand, quickly came in on HD with the DHHD1000 but required much fiddling with the antenna to come in on HD with the Recepter HD. Not sure if this is more a function of the Receptor HD or of WXKS.

For all three AM HD Radio stations, the Receptor HD had two major quirks.First, it would often flash the “acquiring HD signal” icon for stations that don’t even have an IBOC transmitter.Obviously it wasn’t getting an HD signal, but this could be confusing to non-technical users.

Second, and more problematic, was an unusual tendency for the Receptor HD to “lose the signal” and dim the audio volume drastically.This would happen for a few seconds at least two or three times per minute on anything but the strongest stations.VERY careful positioning of the AM loop antenna helped mitigate that, but regardless...overall I’d have to give a firm nod to the Directed Electronics for AM sensitivity.

In terms of features, the Receptor HD and DHHD1000 have a similar features list; multiple presets, movable speakers, dimming display, two alarm clocks, headphones out and aux input.Unfortunately, for the DHHD1000, the Receptor HD is better at most of these functions: the Receptor has much more (and adjustable) bass and thus sounds much better.The physical design is more “sexy”.The display’s dimming is a little better since it’s light characters on a dark background (the DHHD1000 is the reverse).The presets are a little easier to set, too.

I got my DHHD1000 through a broadcaster’s special that reduced the total price to under $120, which is a perfectly fair price for it.However, at the MSRP of $250 it just doesn’t stack up as well as the Boston Acoustics Receptor HD considering I can get the Receptor HD for the same price at any Radio Shack.I suspect that like most electronics, the DHHD1000 will come down in price over time…after all, the Receptor HD originally cost $500.So as the price drops the DHHD1000 will become far more competitive.

Let’s bring the Sangean HDT-1 into the mixI also have a Sangean HDT-1 component home stereo-style HD Radio tuner to compare against.The results were interesting, although not tremendously so.One thing that was immediately apparent was that the Sangean decodes HD audio with a bit more delay.When playing HD, both the DHHD1000 and the Receptor HD were perfectly synchronized…but the Sangean was about a quarter-second behind them. I'm told this is not unusual and that sometimes even two radio s of the same model will have slightly different delays...although the delay ratio between analog and digital will remain consistent within each receiver.

The Sangean also seemed no better than either tabletop radio in the sensitivity department; it was able to receive HD signals about the same when using the same antenna.Interestingly, while the Sangean’s included ribbon dipole antenna looks slightly “fancier” than the DHHD1000’s wire dipole, the wire dipole yielded slightly but noticeably better reception.

I’ll have to put all three units on the bench to really tell if there’s any difference in receiver sensitivity between these tabletop and component tuners…but at first glance they all seem about the same.That is to say: they’re no Onkyo T-9090’s, but they’re pretty decent with a good antenna.This is in marked contrast to many analog radios, where tabletop & clock radios typically are terrible receivers with any antenna, and component tuners are a mixed bag.

One can only hope that this trend of HD Radios being generally decent receivers continues.I also hope that manufacturers get better about including quality antennas with their radios, since it makes such a marked difference.

A bit about the stations I’m hearingWhile this has little to do with the radio itself, I did want to comment on the wide variety of quality I hear on the 25+ HD Radio stations you can hear in Boston.First, I noticed that most of the stations have synchronized the delay of their analog programming to the digital programming.So the blend is not very noticeable.However, about a fifth haven't quite gotten sync'd perfectly (so there's an audible changeover), and two FM stations (as of 4/18/07), which shall remain nameless to protect the guilty, appear to not be delaying their analog signal at all.When those two blend to HD, you hear the last five seconds or so of programming over again…that must be maddening to in-car listeners on the fringe!

There’s a four-station cluster that shares a master antenna with some sort of problem that causes their stations’ HD2 audio to drop out for a second or two at least 3-4 times a minute.I’m told they’re working on it, but the problem has been there for a while. (update 4/21/07: sounds like they've fixed the problem)

I did notice that a handful of stations are running their processing pretty much the same on both analog and digital, but the digital one is perhaps 1 or 2 dB louder.I think this could be a smart idea – it really lets you know you’re hearing the HD signal now, and the added volume gives a psychological boost to the impression that it’s “better”.

However, several stations were obviously running their HD audio much quieter than the analog.I’m torn here; one of HD Radio’s big promises was an end to the “loudness wars” that have done nothing but craze your Program Director while causing widespread listener fatigue.But it’s jarring to hear the volume drop by -3 or -6dB when it blends to HD.Ideally you’d back off the processing on your analog but we all know how well that lead balloon will fly.There’s no simple solution here, but I don’t think simply letting HD sound quieter is the answer.It’s too easy for people to assume that quieter = poorer audio quality.

I’ve heard that the HDC codec inherent to HD Radio handles music better than voice at low bitrates.This would be consistent with what I’m hearing on our local AM stations: WBZ (all news/talk) and WMKI/WXKS (Radio Disney music and Spanish music, respectively).There was a small but discernible increase in audio artifacts on WBZ.I didn’t notice any artifacts on any of the FM stations, but nobody around here is multicasting more than one extra channel so I wasn’t expecting many artifacts, either.

The quality of PAD (Programming-Associated Data) was all over the map.Some stations had some really terrible PAD, with just call letters.One station’s call letters had been replaced by the phrase “iBiquity Digital Corporation” even though the secondary PAD field had artist/title info.At the other extreme, another station had call letters alternating with the station’s catch phrase in the main field, and in the secondary field showed artist/title and then the current Boston temperature.It would also cycle in “next track coming up” info as well.Nicely done!

As of now, no station is really taking full advantage of PAD to offer information that’s timely, useful and beyond what the listener can get just from listening.Info like more comprehensive weather conditions, a running transcript on talk shows, trivia about the artist currently playing and special contest/giveaway codes, etc. etc. etc.The surface has only barely been scratched here.Still, give it time; it took 10 years before stations started really embracing PAD via RBDS.

However, getting back to the audio…it does concern me how I don’t quite see stations taking their multicast channels, or HD in general, quite as seriously as their analog signal.Many of them seem to have the attitude that “It’s important and we’re working on it”, but it’s nowhere near the level of importance of the main analog signal; for example, if your main FM was dropping out for a few seconds every minute…you’d better believe the problem would be fixed within a week at most; not allowed to continue for months.

I confess I understand the lack of urgency…there aren’t that many radios out there yet, and the lack of commercials makes it hard to monetize multicasting.Still, I do hope that stations soon consider their multicast channels as critical as their main channels; after all, the listeners certainly will.

ConclusionsWith an MSRP of $250, the DHHD1000 would seem to be in direct competition with the Boston Acoustics “Receptor HD” tabletop clock radio.Unfortunately, the BA sounds better, looks better and has better features, all for the same price.In addition, when using the same antennas, putting the tuners head to head yielded roughly the same receiver sensitivity.

This is not to say the DHHD is a bad radio.Overall it’s pretty good, and out of the box it’s supplied FM dipole is far superior to the BA’s supplied “rat tail”…giving it a distinct edge to the non-technical user. And if the price follows a typical pattern of dropping over time as R&D costs are recouped, then I would consider it a worthy contender in the tabletop radio market.

My typical use for the DHHD has been to listen to WBUR (our local NPR news station) while at work.My office building in the heart of metro Boston has metal walls and several sources of electrical interference…so getting static-free reception of WBUR (even with their hefty signal) is usually a crapshoot at best.This is where HD Radio has really shined: once I get an HD signal – the audio blends seamlessly and just plain sounds good.No clicks, no static, no hiss…just clear audio.It’s easy to overlook until it goes away – then suddenly it’s really noticeable.All-in-all, I’m happy to have this little tabletop radio sitting on my desk doing exactly what I need it to.

The "MEMO" button is what you use to store presets. It's short for "Memory".

I don't have the radio or manual in front of me at the moment, but IIRC, you manually tune to the station you to set as a preset, then press MEMO repeatedly. The preset number will appear in the upper left corner of the display and count upwards as you press MEMO. Stop when reach the present number you want, then press PRESET to save it.

Once you've programmed your presets, you hit the PRESET button to cycle between present-tuning and manual-tuning modes.

Just purchased used the Directed HD tabletop radio yesterday, the user's manual is terrible! How does a person set the clock, or make the radio dimmer as it is very bright at night when I'm trying to sleep ?

With the radio powered up, press the MENU button. Twist the big silver knob until 1.CLOCK SET is highlighted. Press in the knob to select. Clock set will appear and the hours blinking. Twist to change the number, press knob to set it; now minutes will flash. Twist to change, press to set. Now AM/PM will flash. Again, twist to change, press to set. You can cycle through by pressing the knob if you missed a number. Press MENU twice when done.

To set the dimmer, press MENU. Twist the knob until 2.LCD CONTROL is highlighted. Press knob in to select. Repeat to select 2.DIM. The dimmer screen is now visible. Twist the knob to set the level, then press the knob in to lock it. Press MENU twice when done to back out of the menu structure. But be advised, even at its lowest setting, the display is still pretty bright - as I mentioned in the above review.

Aaron Read : Thankyou for your info you gave me on 12/09/2013, you should have been the one writing the manual, I guess alot was lost in the translation from Chinese into English atleast I had a hard time understanding the manual . Thanks again Tom

About Me

Fried Bagels is Aaron Read, a National Public Radio and college radio veteran, having worked for over a dozen non-commercial stations since 1996, and serving as General Manager to NPR affiliate WEOS for four years. He is a SBE Certified Broadcast Technologist, and relishes his "jack of all trades" reputation more than he probably should. He currently works as IT/Engineering Director for Rhode Island Public Radio
Any opinions expressed on this blog are Aaron's alone, and do not necessarily represent those of his clients or employers.